Go-kart, or kart, as it's shortened today--the name probably brings back memories of your youth. It was most likely a crude, homemade yard vehicle that you and your siblings had a ball racing in the backyard. That was then; this is now.

You may have never had thoughts of racing this rude vehicle in a controlled environment, but today, it's an entirely different situation. The sport has matured into a professionally run, worldwide deal that serves as an initial learning ground for many past, present, and future professional race car drivers.

The sport is run on both dirt and pavement, with a variety of track configurations. And it's not just for boys anymore, as up to 10 percent of the drivers are now girls.

But as kart racing official Tony Barton explains, "Many that race the karts are out here for one big reason--to have fun and experience the thrill of competition. And they can do it for a long time as there is no age limit. The youngest drivers allowed have to be five years old, and we have one driver who is 75 years old!"

But if professional competition is your bag, you have to be impressed with the prestigious kart alumni list of drivers whose racing skills were honed by karting when they were young. Included are the likes of most Formula 1 drivers, along with NASCAR drivers Jeff Gordon, Tony Stewart, Jeff and Ward Burton, Jamie McMurray, John Wood, and Brian Vickers, among others. In the IRL, there are both Sam Hornish Jr. and Sarah Fisher.

One of the huge advantages of Kart racing in the 2000s is its great versatility. Cars from a number of different classes run on both dirt and pavement, on several different sizes of ovals, along with the road courses at tracks like Daytona, Mid-Ohio, and other national tracks.